In the wake of the Parkland and Santa Fe shootings, the push to arm more teachers has gathered momentum. Here, Texan staff explain why. Interviews and pictures: Spike Johnson

For the past 18 months, the British photojournalist Spike Johnson has been touring Texan high schools, talking to the armed superintendents who work there and who believe passionately that civilians have a greater role to play in protecting American children. At least 10 states across the US now allow school staff access to firearms, kept in lock boxes or inside vehicles, in a scheme known as the school marshal programme. In Texas, though, more than 170 schools go a step further, allowing employees to carry weapons under a shirt or in an ankle holster.